We conducted a quantitative experiment to determine the performance characteristics of non-speech vocalization for discrete input generation in comparison to existing speech and keyboard input methods. The results from the study validated our hypothesis that non-speech voice input can offer significantly faster discrete input compared to a speech-based input method by as much as 50%. Based on this and other promising results from the study, we built a prototype system called the Voice Game Controller that augments traditional speech-based input methods with non-speech voice input methods to make computer games originally designed for the keyboard and mouse playable using voice only. Our preliminary evaluation of the prototype indicates that the Voice Game Controller greatly expands the scope of computer games that can be played hands-free using just voice, to include games that were difficult or impractical to play using previous speech-based methods.